Pre-set torque release wrench



May 12, 1964 F. W. LIVERMONT PRE-SET TORQUE RELEASE WRENCH Original Filed June 50, 1960 IN V EN TOR.

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M wp @mf/Ml W uz. MB W United States Patent O 3,132,548 PRE-SET TORQUE RELEASE WRENCH Frank W. lrirermont, deceased, late of Duarte, Calif., by

Milford S.. Zimmerman, executor, Pasadena, Calif., assigner to Reed Roller Bit Company, Houston, Tex., a corporation of Texas Continuation ol abandoned application Ser. No. 40,08), .lune 30, 1960. This application Sept. 25, 1961, Ser. No. ldihil Claims. (Cl. lll-525) This invention relates to torque wrenches and is particularly directed to improvements in torque release wrenches of the general type` shown in the Livermont Patent No. 2,887,921, granted May 26, 1959.

Torque release wrenches of the type shown in that patent have a spring-loaded toggle mechanism mounted within a tubular handle. A wrench head is provided with a laterally extending arm projecting into one end of the handle for actuating the toggle mechanism. The arm is connected to the handle by a transverse pivot pin. When the wrench head is engaged with a nut or other workpiece and increasing torque load is applied to the handle, the toggle mechanism breaks or trips when the magnitude of the torque load reaches that for which the internal load spring is set. Accordingly, the operator feels and hears a sharp click when the toggle mechanism releases under load.

Torque wrenches of the general type shown in said patent commonly employ a threaded device for adjusting the compression of the load spring and thereby changing the torque load setting of the wrench. Moreover, such devices are provided with scale means to provide a visual indication to the operator of the adjusted torque load setting.

The disadvantage of that type adjustable torque release wrench is that a separate wrench is required for each type of wrench head since the wrench heads cannot be detachably connected to the torque transmitting arm. A detachable connection at that point would enable wrench heads of various types to be installed but the distance from the effective axis of the wrench head to the pivot pin connecting the `arm to the wrench handle would vary depending upon the particular form of wrench head and this would result in error of the indicated torque load setting as shown by the scale.

Accordingly, it is an important object of the present invention to provide a torque wrench assembly particularly adapted for use with interchangeable wrench heads.

Another object is to provide such a device having novel means for adjusting the compression of the load spring. ln using a device of this type the operator assembles the particular wrench head and any extensions, adapters, etc. on the end of the torque-receiving arm and then takes the entire assembly to a torque measuring instrument. An external rotary sleeve on the handle has an inner part which engages `an internal screw within the handle for changing the compression of the internal load spring. The handle sleeve is rotated until the torque measuring instrument shows that the toggle mechanism within the wrench is tripping at the desired torque value. No calculations or computations by the operator are required to cornpensate t'or lengths of extensions employed between the Wrench handle and the wrench head. A torque measuring instrument of the type referred to is shown in the Livermont Patent No. 2,703,976, granted March 14, 1955, and in the co-pending Livermont application entitled Torque Measuring Device, Serial No. 40,031, tiled lune 30, 1960, now Patent No. 3,079,785. The handle sleeve may remain on the wrench handle and be grasped manually for applying torque load to the wrench handle, or this handle sleeve may be disconnected by telescopic movement from the remainder of the wrench parts to prevent further change in the setting of the load spring screw.

Other and more detailed objects will appear hereinalter.

ln the drawings:

FIGURE l is a top plan View showing a preferred embodiment of this invention.

FIGURE 2 is a side elevational view, partly in section.

FIGURE 3 is a fragmentary sectional View of the wrench handle and associated parts at the opposite end of the device from the Wrench head.

FIGURE 4 is a sectional view showing the detachable wrench handle sleeve for adjusting the compression ot the load spring.

FlGURl-. 5 is a sectional elevational View similar t0 FIGURE 3 but showing the special tool in operative position.

Referring to the drawings, the torque wrench assembly, generally designated l0, includes a tubular handle lll which is open at both ends. A torque transmitting arm l2 projects into one end of the handle lll and is connected to the handle by means of the transverse pivot pin 13. The handle 1l serves as a housing for the toggle mechanism and includes a toggle link l5 interposed between transverse pins i6 and i7 mounted on the arm l2 and block lll, respectively. The block i8 is mounted for axial movement within the interior of the handle ll and is provided with a roller i9 which rolls along the surface 2li provided within the handle ll. A coil spring 2l under compression engages the block lli at one end and is engaged at the other end by the adjusting screw 22. This screw 22 has external threads which engage within the internal threads 23 provided within the housing ll. at a location remote from the pivot pin i3.

A detachable wrench head 2S of any desired type is connected to the extending end of the arm l2 by means of the dove-tail joint generally designated 26. This dovetail joint or connection may be similar to that shown in the Livermont Reissue Patent No. 24,831 dated May 3l, 1960 and is preferably of the particular construction shown in the co-pending Livermont application Serial No. 852,379, tiled November l2, 1959, now Patent No. 3,039,340, and entitled Detachable Connection for Wrench Heads. rThe wrench head Z5 may be connected directly .to the arm l2 as shown in the drawings, or any suitable form of straight, angled, offset or other extension interposed therebetween.

A cover grip Sill is mounted on the outer surface 31 of the handle ll and this cover grip has an end portion 32 which serves to close the opening in the threaded end of the handle ll. This end portion 32 has a central resilient end iiange 33 having a transverse slit 34.

The rotary handle sleeve dll shown in FIGURE 4 cornprises cylindrical shell 4l provided with an end wall 42 and a central axial post or stake d3. The projecting end dd of the stake d3, is beveled and terminates within the interior of the shell d1. The stake d3 is non-circular in cross-section and is shaped to slide into the corresponding non-circular central opening 4S provided in the screw 22. The rotary handle sleeve d@ may be brought into operative position by sliding the shell 41 in telescopic relation over the end of the handle 1l and over the grip sleeve 3i). This causes the forward end ot the stake 43 to pass through the resilient slit wall 33 and to slide into the central opening dit in the nut 22. When parts 41 and 1l are in the relative axial positon shown in FIG- URE 5 the shell 4l may be manually gripped and rotated with respect to the handle ll to cause the adjusting screw 22 to change the compression of the spring 2l. This action serves to change the magnitude of the force applied by the spring 2l to the block ld and thereby changes the torque setting value at which the toggle mechanism 3 14 trips or breaks under torque load applied to the handle 11.

In operation, the desired form of wrench head 25 together with any extensions are connected to the projecting end of the torque transmitting arm 12. This is accomplished by means of the dove-tail connection 26. The device as thus assembled is taken to a torque measuring instrument of the type described above, and a load is applied to the handle thereby transmitting torque through the arm 12 to the wrench head 25. If the toggle mechanism 1d does not trip or break at the desired torque value, the handle sleeve 40 is installed in position as shown in FIGURE and rotated to cause the screw 22 to change the compression of the spring 21. The handle sleeve 40 may be maintained in assembled relationship while the torque wrench assembly is again used with the measuring instrument to determine the adjusted torque load setting. The handle sleeve 40 is used to adjust the position of the screw 22 until the torque load setting as shown by the instrument equals the value desired. The handle sleeve 40 is then withdrawn from operative position and the torque wrench assembly with the same wrench head and any adapters, extensions, etc. are taken as a unit to the work.

Not only may the detachable handle sleeve 40 be used for applying torque load to the torque measuring instrument, as described above, but it may also be left in place on the wrench handle and gripped manually for applying torque load to the work for tightening bolts, nuts, etc. Thus, the detachable handle sleeve 40 may be left in place on the wrench handle or disassembled, as desired.

This application is a continuation of the co-pending application of Frank W. Livermont, Serial No. 40,080, tiled l' une 30, 1960, now abandoned.

Having fully described this invention, it is to be understood that it is not to be limited to the details herein set forth but that it is ofthe full scope of the appended claims.

What is claimed is:

1. In a torque wrench assembly the combination of: a tubular handle having an open end and having internal threads near the other end, a torque-transmitting arm projecting into the open end of said handle, pivot means connecting said arm and said handle, a block mounted for axial movement within the handle, toggle means within the handle interposed between said arm and said block, a compression spring within the handle acting to move the block axially, a screw engaging said internal threads in said handle and acting to compress the spring, a cover grip mounted on said other end of the handle and having a flexible apertured flange, the screw having a central noncircular opening for reception of an adjusting member inserted through said flange.

2. In a torque wrench assembly the combination of: a tubular handle having an open end and having internal threads near the other end, a torque-transmitting arm projecting into the open end of said handle, pivot means connecting said handle and said arm, a block mounted for axial movement within the handle, toggle means within the handle interposed between said arm and said block, a compression spring within the handle acting to move the block axially, a screw engaging said internal threads in said housing and acting to compress the spring, the screw having a central non-circular opening, and a handle sleeve member having a shell receiving said other end of the handle in telescopic relation for manually applying a torque load to the wrench assembly, said handle sleeve member also having a central non-circular spike extending into the handle and being slidably received within said screw opening, whereby turning of said handle sleeve member relative to the handle serves to change the degree of compression of said spring, said handle sleeve member with its spike being removable axially from the handle and screw.

3. In a torque wrench assembly, the combination of: a tubular handle, toggle mechanism within the handle, a load spring acting on the toggle mechanism, a screw threaded within the housing and acting to compress the spring, the screw having a central non-circular opening, a handle sleeve member provided with a shell adapted to receive an end of the handle in telescopic relation for manually applying a torque load to the Wrench assembly, said handle sleeve member also having a central noncircular spike fixed relative to said shell and slidably received within said screw opening, whereby turning of the shell relative to the handle serves to change the degree of compression of said spring, said handle sleeve member with its spike being removable axially from the handle and screw.

4. in a torque wrench assembly the combination of: a tubular handle, toggle mechanism within the handle, a load spring acting on the toggle mechanism, an element threaded within the housing and acting to compress the spring, said element having a non-circular part, a handle sleeve member provided with a shell adapted to receive an end of the handle in telescopic relation for manually applying a torque load to the wrench assembly, said handle sleeve member also having a central non-circular element xed relative to said shell and slidably engaging said non-circular part, whereby turning of the shell relative to the handle serves to change the degree of compression of said spring, said handle sleeve member being axially removable from the handle and threaded element.

5. In a torque wrench assembly the combination of: a tubular handle having an open end and having internal threads near the other end, a torque-transmitting arm projecting into the open end of said handle, pivot means connecting said handle and said arm, means for detachably connecting a wrench head to said arm, a block mounted for axial movement within the handle, toggle means within the handle interposed between said. arm and said block, a compression spring within the handle acting to move the block axially, a screw engaging said internal threads in said housing and acting to compress the spring, the screw having a central non-circular opening, and an axially removable sleeve handle member provided with a shell adapted to receive said other end of the handle in telescopic relation for manually applying a torque load to the wrench assembly, said sleeve handle member also having a central non-circular axial spike fixed relative to said shell and slidably received within said screw opening, whereby turning of the shell relative to the handle serves to change the degree of compression of said spring.

References Cited in the file of this patent UNITED STATES PATENTS 2,576,751 Dortmund Nov. 27, 1951 2,769,471 Cheney Nov. 26, 1956 2,887,921 Livermont May 26, 1959 2,918,834 Cranford Dec. 29, 1959 

1. IN A TORQUE WRENCH ASSEMBLY THE COMBINATION OF: A TUBULAR HANDLE HAVING AN OPEN END AND HAVING INTERNAL THREADS NEAR THE OTHER END A TORQUE-TRANSMITTING ARM PROJECTING INTO THE OPEN END OF SAID HANDLE, PIVOT MEANS CONNECTING SAID ARM AND SAID HANDLE, A BLOCK MOUNTED FOR AXIAL MOVEMENT WITHIN THE HANDLE, TOGGLE MEANS WITHIN THE HANDLE INTERPOSED BETWEEN SAID ARM AND SAID BLOCK, A COMPRESSION SPRING WITHIN THE HANDLE ACTING TO MOVE THE BLOCK AXIALLY, A SCREW ENGAGING SAID INTERNAL THREADS IN SAID HANDLE AND ACTING TO COMPRESS THE SPRING, A COVER GRIP MOUNTED ON SAID OTHER END OF THE HANDLE AND HAVING A FLEXIBLE APERTURED FLANGE, THE SCREW HAVING A CENTRAL NONCIRCULAR OPENING FOR RECEPTION OF AN ADJUSTING MEMBER INSERTED THROUGH SAID FLANGE. 